Just out of interest....
John Lennon's MKII mellotron has never gone up for auction and is alive and not particularly well in a famous record producer's apartment. We've been to see it and can guarantee it is the genuine article because it was one of only six Black and Gold MKIIs built. Lennon's machine was also not sold in a Christie's auction back in the 90's. It could well be not sold again soon!
Best,
Martin